The European Commission made a brief statement today announcing that it has informed thirteen companies supplying optical disk drives -- such as CD and DVD drive components -- that it suspects them of participating in a "worldwide cartel."

In a released statement, the Commission said the companies are accused of rigging bids over a five-year period:

"The Commission has concerns that those suppliers may have coordinated their behaviour in bidding events organised by two major original equipment manufacturers for optical disk drives used in personal computers (desktops and notebooks) and in servers.

By sending a statement of objections -- like a charge sheet of formal complaints -- to each company, it formalizes the antitrust process and marks the beginning of a fully-fledged investigation, in which heavy fines could be imposed.

"This behaviour, if established, may have ultimately affected customers that bought optical disk drives manufactured by the companies concerned," the note from Brussels added.

But none of the companies involved were mentioned by name, as per Europe's policy on dealing with cartels. Should the group of companies fall foul of antitrust law, they will be named in due course.

Cartels are groups of companies that join together to fix prices, limit production of a good or produce, or share markets or customers between them, which ultimately pushes out the competition.

EU authorities can impose fines of up to 10 percent of a company's global annual turnover. However, since 2008, companies found to have broken EU cartel and antitrust law can settle in return for a smaller fine.